bug#9402: list-colors-display

[Eli Zaretskii <eliz@gnu.org>]

> From: Juri Linkov <juri@jurta.org>
> Cc: 9402@debbugs.gnu.org
> Date: Wed, 31 Aug 2011 19:27:45 +0300
> 
> >> Another question is why the face definition of `region' has
> >> platform-specific colors for GTK and NS, but not for Windows.
> >
> > I would actually turn the table and ask why the heck do we have
> > system-specific defaults for GTK and NS.  I thought Emacs was supposed
> > to behave the same on all platforms, except where it's impossible.
> 
> Emacs should respect the user settings even if they are made on
> system level.

How many users actually change these system-level settings from their
defaults?  My guess is zero.

> Emacs already respects the user's choice of system-specific colors
> on a tty (with `unspecified-fg' and `unspecified-bg') and some other
> system-specific customizations.

You have it backwards.  The _only_ reason Emacs does that is on a tty
is that many text terminals cannot be queried about their colors.
When Emacs can do that, it sets its own default colors.

> I don't remember the goal of trying to look the same on all platforms
> and indeed Emacs already doesn't look the same on different platforms:
> there are different scroll bars, frame decorations, fonts, icons, etc.

These are specific to GUI toolkits and/or window managers.  IOW,
something that is out of Emacs control.  Colors that Emacs uses for
non-default faces do not fall under the same category.

> So Emacs should adapt to the platform defaults as much as possible.

Obviously, I disagree.  Emacs should have the same defaults on all
platforms, as much as possible.  People such as myself who use Emacs
on multiple platforms become very confused when the colors they expect
don't show.